Generally, obesity is defined as an excess of adipose tissue. Clinically, it is generally defined as that amount of adiposity that imparts a health risk. Even mild obesity, at 20% over desirable weight according to standard height-weight charts, may increase the risk for disease and premature death. While the etiology of obesity and diabetes is not entirely overlapping, it is now amply clear that both share appreciable biochemical and physiological components.
The incidence of the metabolic disorders of diabetes and obesity has reached epidemic levels. It has been estimated that over 120 million Americans are clinically over-weight and over 25 million have diabetes, including 1.9 million new cases in 2010 among those aged 20 and older. Obesity and diabetes can cause or contribute to the development of, or at least affect the treatment of, other diseases and disorders such as cardiovascular diseases, stroke, hypertension, kidney failure, asthma, and cancer. The economic burden of diabetes alone was estimated to be over $174 billion per year in 2007. Obesity and diabetes have a major impact on human health and the various national healthcare systems all over the world.
Recently launched weight-loss drugs have failed or have demonstrated limited efficacy and undesirable side effects. Similarly, despite a tremendous medical need, the pharmaceutical industry has realized only limited success developing therapeutics to manage diabetes. The most common therapeutics (sulfonylureas) are not effective and the most promising new drugs (thiazolidinediones) have demonstrated rare but fatal side effects. Thus, there is an urgent need for a more comprehensive understanding of the molecular basis of obesity and diabetes, for tests that allow early detection of predispositions to the disorders, and for more effective pharmaceuticals for preventing and treating the diseases and conditions.